1. Field of the Invention
The invention relates to a vibrator applied to a mobile phone or a pager, and more particularly, to a vibrator producing vibration in different directions.
2. Description of the Prior Art
Along with progress of the semiconductor technology, capacity and weight of many electric devices, such as the watch, the alarm clock, the pager, or the mobile phone, are substantially reduced. These electric devices are portable to arrange schedule or access messages. For achieving the above-mentioned purposes, these electric devices generally send out a reminding signal. For example, a watch or an alarm clock usually sends out a reminding signal at a preset time, and a pager or a mobile phone usually sends out a reminding signal while receiving a telephone call. In general, the reminding signal is a specific sound or a vibration. Since the reminding sound may disturb other people, the effective vibrator is developed.
Please refer to FIG. 1 to FIG. 4. FIG. 1 is an exploded diagram of a vibrator 10 according to the prior art, FIG. 2 is a schematic diagram of a combined vibrator 10 according to the prior art, FIG. 3 is a cross-sectional view of a vibrator 10 along line 3—3 in FIG. 2, and FIG. 4 is a top view of a vibrator 10 without a housing. A cam 16 is installed in the housings 12A, 12B, and the cam 16 rotates on a plane 27 around an axle 26 that is perpendicular to the plane 27 (rotates along direction 25 in FIG. 2). In the housings 12A, 12B, besides the cam 16, two conductive brushes 14A, 14B, and two magnets 18A, 18B are further installed. Two coils 20A, 20B are equipped on the cam 16 to conduct to the conductive sheets 22 and a weight adjuster 15. The magnets 18A, 18B are fixed on the bottom of the housing, and one end of the brushes 14A, 14B is fixed on the housing 12A and the other end is contacted to the conductive sheets 22, as FIG. 2 and FIG. 3 show. With the brushes 14A, 14B, the magnets 18A, 18B, the conductive sheets 22, and the coils 20A, 20B, the cam 16 can joint the housings 12A, 12B to achieve function of a motor (such as a DC motor). As shown in FIG. 2 and FIG. 3, when the brushes 14A, 14B are electrically connected to a driving circuit 24 (such as a battery), the driving circuit 24 can provide power energy to the coils 20A, 20B through the brushes 14A, 14B and the conductive sheets 22. The coils 20A, 20B work as an electromagnet to alternately attract and repel the magnets 18A, 18B, and drive the cam 16 to rotate around the axle 26 along direction 25.
To fully utilize functions of the vibrator 10, the cam is designed in an asymmetric shape (shown in FIG. 1 to FIG. 4), the coils 20A, 20B are designed asymmetric to the axle 26, and the weight adjustor 15 is equipped on one side of the cam 16. These designs make the center of mass 19 of the cam 16 differ from the axle 26 with an eccentric center. The center of mass 19 of the cam 16 projected on the plane 27 substantially differs from a center position of the axle 26 to provide a horizontal vibration parallel to the plane 27. The transmission direction of the vibration is shown as direction 28 in FIG. 1 to FIG. 3.
Please refer to FIG. 5, which is a schematic diagram of another vibrator 30 according to the prior art. The coils 34A, 34B are installed in the housing 32, and the flexible shaft 36 is installed in another side of the housing. One end of the shaft 36 is fixed to the housing 32, and the other end has a magnetic pendulum 38 installed. When the coils 34A, 34B are electrically connected to a driving circuit 44 and receive a periodic power energy, the coils 34A, 34B work as an electromagnet to alternately attract and repel the pendulum 38. The pendulum 38 swings between the coils 34A, 34B and produces a vibration along direction 40.
The conventional vibrators 10, 30 have a limitation of the vibration direction. As shown in FIG. 1 to FIG. 4, the vibrator 10 can only produce a vibration parallel to the plane 27, and can do nothing to the perpendicular vibration. Similarly, as FIG. 5 shows, the vibrator 30 can only produce a vibration along directions 42A, 42B. These conventional vibrators are limited in the vibration direction, and may be easily counteracted. For example, if the vibrator 30 is compressed against the directions 42A, 42B, the vibration will be reduced and counteracted. Similarly, if the vibrator 10 is compressed against the direction 28, the vibration will be also reduced and counteracted.